1. Field of the Disclosure
The present disclosure relates generally to toner cartridges used in electrophotographic imaging devices such as printers or multifunction devices having printing capability and more particularly to a volumetric toner cartridge having a driven platform.
2. Description of the Related Art
In toner cartridge design, it is now common practice to separate the longer lived components from those having a shorter life. This has lead to having the longer lived developing components, such as the developer roll, toner adder roll, doctor blade, the foregoing are also referred to as a developing unit, photoconductive drum, cleaning and charge rollers and a waste bin, to be in separate assemblies from the toner cartridge. The toner supply, which is consumed relatively quickly in comparison to the previously described components, is provided in a reservoir in a separate toner cartridge that mates with the developer unit. The toner cartridge has a reduced number of components and is often referred to as a toner bottle even though it is more than a mere bottle for holding toner.
To deliver the toner from the toner cartridge to the developer unit, an auger in the toner cartridge may be used to feed toner from the toner cartridge via an exit port on the toner cartridge into an entry port on the developer unit and into a second auger that disperses the toner within the developer unit. As the toner is drawn out of the cartridge unit, it is augured through a shutter used for sealing the exit port of the toner cartridge when it is not inserted in the imaging apparatus.
While moving toner through the restriction formed by the shutter, auger and exit port, the opening from the exit port into the toner reservoir in the toner cartridge is relatively air tight. A low pressure condition or vacuum-like condition is created in the toner cartridge as toner is removed, as air cannot enter to fill the void. If the toner cartridge were viewed as being a pump supplying toner from the toner reservoir, this low pressure condition would be analogous to cavitation in a pump. The number of rotations of the auger is used to estimate toner delivery from the toner cartridge. However, low flow due to the discussed pressure differential may lead to inaccuracies in using this approach.
It would be advantageous to have a toner feeding system that provides for more accurate toner delivery and helps to avoid a number of previously mentioned toner delivery failures.